When I first built my soundlab the frequency range was about 0.75 hz to 150Hz, so I slapped on another 10nf capacitor across C14 (5nf) to make it more like .3Hz to 50Hz, which has been more useful.
Could somebody tell me what their does as I would like to find out if it is supposed to be like this or I have a mistake somewhere.
Thanks _________________Stephen
www.Rainsbury.Net

On my Soundlab++ i have a 4N7 on the pcb and i have a switch on the panel to switch in a red Wima 2U2 box polyester for a slow triangle, im not sure of my frequencies as i've not tested them but they flash the led at a snails pace , flick the switch = audio rates.

Here's the link to the build , i love the soundlab , i stuffed a little pre-amp in for the audio out at a later date & it parps away wonderfully , i used ssm2210 matched pair chips back when they were plentifull i use mine for melody / basslines & FX sounds & more

Hmm, I have managed to increase the range significantly by dropping the R94 to 47 ohms, now it goes right down to 0.1Hz. In theory you could drop it even lower, but there comes a point where there won't be enough current to charge C14.
There is however a problem, in that all this extra range appears in only a few degrees at the end of the pot travel, making it difficult to use.
Swapping R90 for a log pot might make it better, or worse, but its late, I am tired and I can't work out which it will be. I think it will make it worse, but I will find out tomorrow. _________________Stephen
www.Rainsbury.Net

I have a Soundlab+ as well, and I have the range switch; in the high range I swing from probably .5Hz (I say probably because my frequency counter bounces around a bit, but that seems to be the most stable point) to 108Hz. In the low range, even at the highest pot setting it's too low for me to make anything out of it.

To be fair, I may not have fresh batteries either....

Good luck getting it to work the way you like. Ray's stuff is pretty straightforward, so a little tinkering ought to be easy to do.

elmegil, thanks just what I needed. That's pretty close to what I get, so I can be pretty sure that I have a good circuit and don't need to start looking for faults. That's an evening saved, thanks again _________________Stephen
www.Rainsbury.Net

After much ferkling about I ended up with the original circuit but replaced C14 with a couple of veropins so I can experiment with different values over the next few weeks.
At the moment I have two 10nF caps soldered in parallel (so thats 20nf) which gives a much lower range.
I haven't measure it yet but it feels better for Hawkwind and Gong type "seagull" sweeps. _________________Stephen
www.Rainsbury.Net

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